TROP2 (trophoblast cell-surface antigen 2): a drug target for breast cancer.

Breast cancer (BC) is the most common diagnosed cancer and the second leading cause of cancer-associated death in women, with the triple negative (TNBC) subtype being characterized by the poorest prognosis. New therapeutic targets are urgently needed to overcome the high metastatic potential, aggressiveness and poor survival of these tumors. Trop2 transmembrane glycoprotein, acting as an intracellular calcium signal transducer, recently emerged as a new potential target in epithelial cancers, in particular in breast cancer. We summarize the key features of Trop2 structure and function, describing the therapeutic strategies targeting this protein in cancer. Particular attention is paid to antibody-drug conjugates (ADCs), actually representing the most successful strategy. ADCs targeting Trop2 recently received an accelerated FDA approval for the therapy of metastatic TNBC. The prospects for these novel ADCs in BC subtypes other than TNBC are discussed, taking into account the main pitfalls relative to Trop2 structure and function.